Anonymous wrote:"apparently son and DIL want to sleep and want the kids to sleep and want quieter rooms."
Re-read this part. Who doesn't want this on vacation?
This really shouldn't be an issue outside of sleeping hours. Make your plans with to hang out with the kids during non-sleeping hours.
THIS. OP, how are you aware of what you yourself wrote (the bold above) yet you're unaware that it's perfectly reasonable on your son's family's part to want this?? Their kids as they get older may be sleeping more lightly. Or are needing more sleep overall as they grow. This change is not a "hill to die on" here, OP. If you make this into A Thing you are going to be rightly thought of as selfish and you'll see less of the whole family. Get a room next door that's not adjoining. You still travel with them and do things with the grandkids on trips -- do you just not understand how lucky you are that they want to travel with you, and that many grandparents would kill to have that kind of positive relationship and interaction?